/Engine/Source/Runtime/OpenGLDrv/Public/OpenGLResources.h
Returns access to the platform-specific native window. This is designed to be used to provide plugins with access to the underlying resource and should be used very carefully or not at all.
The pointer to the native resource or NULL if it not initialized or not supported for this resource type for some reason. AddParam could represent any additional platform-specific data (could be null).
virtual void * GetNativeWindow ( void ** AddParam ) const